Current Status of NewSUBARU

Transcription

1 Current Status of NewSUBARU

2 NewSUBARU Storage Ring Storage Ring Parameters The machine parameters of the 1.5 GeV storage ring are listed in Table I. Although the machine condition remains the same, some of the values are revised according to the new model calculation. Table I Main parameters of the NewSUBARU storage ring in FY2011. Circumference m Bending lattice type modified DBA Number of bending cells 6 Straight sections 4m X 4, 15m X 2 Bending radius 3.22 m Injection energy 1.0 GeV Maximum energy 1.5 GeV RF frequency MHz Betatron tune 6.29 (H), 2.23 (V) Momentum compaction factor Electron energy 1.0 GeV 1.5 GeV RF voltage 100 kv 260 kv Natural energy spread 0.047% % Natural emittance 50 nm 112 nm Maximum beam current 500 ma Operation Status The ring has two user-time operation modes, 1.0 GeV top-up operation mode and 1.5 GeV operation mode. The basic operation time is 9:00-21:00 of weekdays. Monday is used for machine R&D, Tuesday is for 1.5 GeV user time, Wednesday and Thursday are for 1.0 GeV top-up user time, Friday is for 1.0 GeV or 1.5 GeV user time. Night period or weekend is used for machine study and user time with the special mode, single bunch operation and Laser-Compton Gamma ray, if necessary. machine study & special user time 545 hrs (20%) beam down time by machine troubles 27 hrs (1%) machine tuning 239 hrs (10%) beamline commissioning 659 hrs (25%) normal user time 1191 hrs (44%) Figure 1: Machine time in FY2012. The total machine time in FY2011 was 2661 hrs, 115% of that of FY2011, including the beam down time. Fig. 1 shows the breakdown. The beam down time includes not only the down by a failure, but also off-beam periods by a beam abort or others due to the beam instability. The category 'beam line commissioning' had been included in the user time until FY2011. The total of the normal user time and the beam line commissioning in this FY, 1850 hrs, was about 121% of that in FY2011. Time for machine study and special users was 128% of that in FY2011. The down time due to the machine trouble was 1.0%, the same level with that in FY Machine Troubles The machine troubles in FY2012 are listed in Table II. The rate of hardware troubles was increasing. We had troubles in two different timing modules. The synthesizer, which is used as a 500MHz master signal generator, had a trouble in AC-DC units and the signal became noisy. This was not counted in down time because we could continue user operation. We had troubles in 5 magnet power supplies. Machine Study and Special User Time Table III shows the list of machine studies in FY One special theme, a research related to a production of Laser-Compton backscattering γ- ray and its use, took more than 50% of the machine study time. Most of them took place after the completion of the new γ-ray hatch at BL1 in November Most of the study reports are open to the public on the home page of NewSUBARU ( lasti. u-hyogo. ac. jp/ beam_physics/ NewSUBARU). Accelerator Improvements The top-up operation current has been raised from 250 ma to 300 ma since October Fig.2 shows typical operation in these 5 years. This improvement was achieved by longer lifetime as a result of an additional installation and optimization of sextupole magnet families. The harmonic sextupole family named 'S1' was separated to 'S1', 'S3OK', and 'S3LU' and they were connected to the independent power supplies. New vertical kicker magnet system was installed at on of the long straight sections. Its pulse shape was 0.5 ns half sine, a little bit longer than the revolution period. The main purpose of the installation was the accelerator physics research to generate narrow band coherent THz radiation. However it is useful also for various researches and machine parameter measurements.

3 stored beam current (ma) Oct. 2012; 300mA Nov. 2011; 250mA Oct. 2009; 220mA Sep. 2007; 200mA GeV top-up operation 9:00 11:00 13:00 15:00 17:00 time Figure 2: Improvement of top-up operation current in these 5 years. Table II Group Operation Operation RF & Timing Magnet Beam line Utility Table III Figure 3: Newly installed vertical kicker system.. Machine troubles in FY2012. Failure/trouble beam down time (hr) Miss operation (human error) 0.9 Beam loss by a beam instabilities 3.6 Schedule delay by SPring-8 trouble 2.3 Timing module 11.3 Synthesizer (noisy signal) 0.0 Power supply 3.7 Cooling water leak at BL1b 5.2 Electric power down by a thunder 0.4 List of machine studies in FY2012. The unit of study time is counted by shifts (typically 12 hrs). R D theme and special user mode Laser-Compton backscattering γ-rays Parameter tuning for various energy operations Commissioning of visible light profile monitor port SR5 Skew quadrupole coupling correction Coherent synchrotron oscillation feed-back Betatron amplitude dependent orbit shift Coherent synchrotron radiation by chromaticity modulation Linear lattice model confirmation Commissioning of the multi-element corrector Identification of RF noise source (synthesizer trouble) responsible person S. Miyamoto S. Miyamoto study shift

4 Beamlines Takeo Watanabe and Hiroo Kinoshita Center for EUVL, LASTI, University of Hyogo Total nine beamlines are operating in the NewSUBARU synchrotron facility. Four beamlines of BL01, BL03, BL06 and BL11 were constructed until Three beamlines of BL07, BL09 and BL10 were started the operation from BL03B beamline branched from the BL03 beamline propose for the usage of the EUVL (extreme ultraviolet lithography) microscope for the EUVL finished mask inspection. BL09B beamline branched from BL09 beamline for the usage of the usage of the EUV interference lithography to evaluate. And BL09C beamline branched from BL09B beamline for the usage of the thickness measurement of the carbon contamination originated to the resist outgassing during the EUV exposure. BL02 beamline was constructed for the usage of LIGA in BL05 beamline was constracted in response to a demand in the industrial world, that is enhancement of the analysis ability in the soft X-ray region with the development of nanotechnology. The arrangement of the beamlines in the NewSUBARU synchrotron radiation facility is shown in Fig.1. Fig. 1 Beamline arrangement in NewSUBARU. I. BL01 BL01 is a beamline for research and developing new light sources. This beamline is one of two long straight section on NewSUBARU. Optical klystron was installed at this straight section. Upstream side of

5 this beamline (BL01B) is intended to be used for visible and infrared light generated from FEL or SR. Downstream side of this beamline (BL01A) is used for laser Compton scattering gamma-rays source. Gamma-ray beamline hutch just outside of the storage ring tunnel was constructed in 2004 for gamma-ray irradiation experiments. Specifications of this gamma-ray source are listed in Table 1. Table 1. Specification of BL01 gamma beam CO 2 laser Gamma energy : MeV 5W -1.7 MeV) Nd laser 5 W Gamma energy : MeV -17 MeV) *Electron beam energy : GeV *Electron beam current : 250 ma gamma-ray beam divergence : 0.5 mrad II. BL02 The LIGA (abbreviated name of Lithogaphic, Galvanoformung and Abformung) process which consists from deep x-ray lithography, electroforming, and molding process is one of the promising candidates for such 3D micofabrication. More than hundreds aspect ratio for microstructure can be attained by the usa of the higher energy x-rays (4-15 kev) from synchrotron radiation (SR) with deeper penetration depth to the photosensitive resist. In this system we have succeeded to enlarged the exposure area up to A4 size and the fabrication dimension from submicron to millimeter by varying the energy of the x-ray source in accordance with the size of desired microparts. Micostructure with high aspect ratio over several hundreds will bi achieved using the x-rays over 10 kev since high energy x-ray has deep penetration depth to the photo-sensitive resist materials. Whereas, in the case of lithography for low energy x-rays from 1 kev to 2 kev, submicron structures with high aspect ratio will be achieved using the x-rays mask with precise line-width and thinner absorber, since low energy x-rays has low penetration depth. Based on this principle, the beamilne for x-ray exposure have constructed with continuous selectivity of x-rays frpm 100 ev to 15 kev by using the x-ray mirrors (plane and cylindrical mirror) and Be film filters. The horizontal angle of the outgoing SR could be obtained up to 12.5 mrad, which corresponds to the horizontal size of 220 mm (A4 horizontal size) at the exposure position. The second characteristic performance of the beamline is the high efficiency differential pumping system. This was necessary for maintain the vacuum difference between the storage ring (<10-9 Pa) and the end-station (<10-9 Pa) at which gasses for substrate cooling will be introduced in the exposure apparatus. The flexibility for the shapes and functions of microstructure will be enlarged by achieving 3D microfabrication process using multi step exposure at various configuration between x-ray mask and substrates. The relative positions between x-ray mask and substrates, tilt and rotation angle to the SR incident direction can be moved simultaneously during SR exposure using 5 axis stages. The movement of each axis is controlled by the PC in terms of the scanning speeds, scanning length, and repetition number. In order to decrease the heat load of sample substrate suffered during SR irradiation helium introduction and substrate cooling mechanism were alse equipped. Specification of spectrometer is listed in Table 2. Table 2. Specification of the LIGA exposure system Optics Plane and cylindrical mirror, Be filters Exposure energy kev, and 4 15 kev Exposure method Proximity and multi step exposure Wafer size A4 or 8 inch Exposure area 230 mm(h) 300 mm(v) Exposure environment < 1 atm (He-gas)

6 III. BL03 BL03 is a beamline for the developing the next generation lithographic technology so called extreme ultraviolet lithography (EUVL). The exposure tool is installed at the end station. Using this exposure tool, the research and development of the next generation lithography such as the less than 70 nm node is going on process. The exposure wavelength is 13.5 nm. The semiconductor industry plays a very important role in the information technology (IT). In 2006, 256 Gbit DRAM with a gate length of 70 nm will be demanded in the IT industry. The extreme ultraviolet lithography (EUVL) is a promise technology for fabricating a fine pattern less than 70 nm. To meet this schedule, this technology has to be developed in the pilot line until As for the practical use, it is very important that both to achieve large exposure area and to fabricate fine patterns. Therefore, at Himeji Institute of Technology, large exposure field EUV camera consists of three aspherical mirrors was developed. First in the world, we fabricated 60 nm line and space pattern in the large exposure area of 10 mm 10 mm on a wafer. Furthermore, BL03B beamline branches from the BL03 beamline propose for the usage of the EUVL microscope for the EUVL finished mask inspection. Table 3. Spectification of the exposure tool (ETS-1) Imaging optics Three aspherical mirrors Exposure wavelength 13.5 nm Numerical aperture 0.1 Demagnification 1/5 Resolution 60 nm Depth of focus 0.9 µm Exposure area (static) 30 mm 1 mm Exposure area (scanning) 30 mm 28 mm Mask size 4 inch, 8 inch, and ULE 6025 Wafer size 8 inch Exposure environment In vacuum IV. BL05 BL05 was constructed in response to a demand in the industrial world, that is enhancement of the analysis ability in the soft x-ray region with the development of nanotechnology. BL05 consists of two branch lines for use in the wide range from 50 ev to 4000 ev. BL05A and BL05B are designed to cover the energy range of ev and ev, respectively. The incident beam from the bending magnet is provided for two branch lines through different windows of a mask. Therefore, these two branch lines can be employed simultaneously. 1) The double crystal monochromator was installed at the BL05A. InSb crystals and Si crystals are prepared for a double-crystal monochromator. Toroidal mirrors are used as a pre-mirror and a focusing mirror of BL05A. XAFS measurement in the total electron yield mode and fluorescence XAFS measurement using SSD (SII Vortex) can be performed. The fluorescence XAFS spectra can be measured for samples at the end station filled with He gas. Table 4. Monochromator specification Monochromator Double crystal monochromator Monochromator crystals InSb(111), Si(111) ev Resolution E/ E=3000 2) The constant-deviation monochromator consisting of a demagnifying spherical mirror and a varied-line-spacing plane grating (VLSPG), which can provide high resolution, simple wavelength scanning with fixed slits, was mounted on BL05B. The optical system consists of a first mirror (M0), a second mirror (M1), an entrance slit (S1), a pre-mirror (M2), and three kinds of plane grating (G), an exit slit (S2) and a focusing mirror (M3). The including

7 angle of the monochromator is 175. Two measurement chambers are prepared at the end station of BL05B. The XAFS spectra in the total electron yield mode and fluorescence XAFS spectra using SDD (EDAX) can be measured in a high vacuum chamber. In addition, the photoelectron spectrum can be measured using spherical electron analyzer (VG Sienta, R3000) in an ultra high-vacuum chamber. The chambers can be replaced by each other within 1 hour. Monochromator Grating Resolution Table 5. Monochromator specification Varied-line-spacing plane grating monochromator 100 l/mm, 300 l/mm, 800 mm/l ev E/ E=3000 V. BL06 BL06 has been mainly developed for irradiation experiments such as photochemical reaction, SR-CVD, photo-etching, surface modification. The white radiation beam from bending magnet is introduced to the sample stage using a pair of mirror, whose incident angle was 3. The SR at BL06 sample stage had a continuous spectrum from IR to soft x-ray, which was lower than 1 kev. A VI. BL07A and BL07B This beamline was designed for the development of new materials by SR technology. This beamline consists of two branch lines, which are provided with an incident beam from a 3-m undulator by switching the first mirror. One of them is a high photon-flux beamline with a multilayered-mirror monochromator for the study of SR-process (BL07A) and another is a high-resolution beamline with a varied line spacing grating monochromator for the evaluation of nano-structure characteristics by SR-spectroscopy (BL07B). The useful range of emitted photons from 50 to 800 ev is covered at both beamlines. The light source of BL07 is a 3-m length planar undulator, which consists of 29 sets of permanent magnets, a period length of which is 76 mm. The incident beam from the undulator is provided for two branch lines by translational switching of first mirror. differential pumping system can be utilized for experiments in a gas atmosphere, which is difficult in the soft x-ray region. A sample holder can install four pieces of samples at a time. By using heater set in the sample holder, the sample can be heated from room temperature to 220 C. The temperature of sample is monitored using a Cr-Al thermocouple mounted on the sample holder. 1) BL07A The multilayered-mirror (MLM) monochromator, which has high reflectivity in the soft X-ray region, was installed at the BL07A. It consists of a switching mirror chamber, a slit chamber, a MLM monochromator, a filter chamber and a reaction chamber. To obtain a large photon flux, we decided to use only first mirror (switching mirror), M0, for focusing. The MLM monochromator is designed to cover an energy range of up to about 800 ev by combination of three kinds of mirror pairs with 4 kinds of filter. The flux deliver by this design is estimated to be between a maximum of photons/s at 95 ev and a minimum photons/s at 300 ev for a 500 ma ring current. Energy range (ev) Material spacing Thickness Ratio Table 6. Summary of BL07A. Multilayer mirror number of layers Filter E/E material thickness Al 100 nm Mo/Si 20 nm % None Mo/B 4 C 11 nm % Ag 100 nm Ni/C 5 nm % Cr 500 nm Ni 500 nm

8 2) BL07B The constant-deviation monochromator consisting of a demagnifying spherical mirror and varied line spacing plane grating (VLSPG), which can provide to high resolution, simple wavelength scanning with fixed slits, was mounted on BL07B. The optical system consists of a first mirror (M0), a entrance slit (S1), a premirror (M1), and three kinds of plane grating (G), an exit slit (S2) and a focusing mirror (M2). The monochromator is designed to cover the energy range ev with three gratings, of which including angle are 168. The VLSPG has been well known to obtain high resolution in extreme ultraviolet region by diminishing various kinds of aberration. The total resolving power about 3000 can be realized in the whole energy region. Table 7. Monocromator specification Mount type Hettrick-Underwood type Grating G1, G2, G3 Plane VLS (600 l/mm, 1200 l/mm, 2400 l/mm) ev, ev, ev Resolving power (E/ E) 3000 VII. BL9 A purpose of this beamline is studies on a soft x-ray interferometry or a holographic exposure experiment with making use of highly brilliant and coherent photon beams radiated from 11 m long undulator in NewSUBARU. BL09 consists of M0 mirror, M1 mirror, G grating and M2 and M3 mirror. M0 and M3 mirrors are used for horizontal deflection and beam convergence, M1 is used for vertical beam convergence at the exit slit, and M2 is used for vertical deflection and beam convergence. A monochromator is constructed by M1 and a plane grating. The maximum acceptance of the undulator beam is 0.64 mrad in horizontal and 0.27 mrad in vertical. The acceptance can be restricted by 4-jaw slits equipped at upstream of the M0 mirror. BL09B beamline branched from BL09 beamline for the usage of the EUV interference lithography for the evaluation of the exposure characteristics of EUV resist. Coherence length of 1 mm at the resist exposure position was achieved using BL09B beamilne. And BL09C beamline branched from BL09B beamline for the usage of the thickness measurement of the carbon contamination originated to the resist outgassing during the EUV exposure. Table 8. Monochromator specification Mount type Hettrick-Underwood type Grating Plane VLS (900 l/mm) ev Resolving power (E/ E) 3000 VIII. BL10 BL10 is for the global use in the Himeji Institute of Technology. M0 mirror is used for horizontal deflection and beam convergence, M1 is used for vertical beam convergence at the exit slit, and M2 is used for vertical deflection and beam convergence. A monochromator is constructed by M1 and a plane grating. At the beginning, the multiplayers reflectiveity measurement was carried out at this beamline. The characteristics of this beamline and the result of the Mo/Si multiplayers measurement are carried out for the development of the EUVL mask techmology. BL10 utilizes a monochromator of the varied line spacing plane grating monochromator (VLS-PGM). The line density of the monochromator in central region of the grating is 600 lines/mm. The reflectometer is a two axis vacuum goniometer using two Huber goniometers. One axis carries the sample, which may for examplee be a mirror at the center of the reflectometer vacuum tank ( -motion). The other ( -motion) carries the detector on a rotating arm. In addition there are through-cacuum linear motions to translate the sample in two orthogonal directions (x,y). All motors are controlled by computer. The sample itself is mounted on a kinematic holder. The controlstage monochromator rotation, and data analysis were program

9 using LABVIEW software. The reflectivity result obtained at BL10 has a good agreement with that at LBNL. The mirso-csm tool was adapted at the most downstream of the BL10 beamline fot the EUV mask defect inspection. This too is very effective for the inspection of the actinic patterned mask. Table 9. Monochromator specification Mount type Hettrick-Underwood type Grating Plane VLS (600 l/mm) ev Resolving power (E/ E) 1000 IX. BL11 A beam line BL11 is constructed for exposure Hard X-ray Lithography (DXL) in the LIGA (German acronym for Lithographite Galvanoformung and Abformung) process. LIGA process, that utilizes a useful industrial application of SR, is one of the promising technologies for fabrication of extremely tall three-dimensional microstructures with a large aspect ratio. This process was invented at the Institut Fur Mikrostrukturtechnik (IMT) of the Karlstuhe Nuclear Center (KfK) in Microstructures with height of over a few hundreds µm have been widely applied to various fields such as micro-mechanics, micro-optics, sensor and actuator technology, chemical, medical and biological engineering, and so on. This beam line was designed by the criteria ; photon energy range 4 kev to 6 kev, a beam spot size on the exposure stage 50 5 mm 2, a density of total irradiated photons photons/cm 2. BL11 of an absorber chamber, a first-mirror chamber (M1), a second-mirror chamber (M2), a 4-way slit chamber, a Be window chamber, and an exposure chamber. The second pre-mirror is bent elliptically using a bending mechanism. Fine bending adjustment of the M2 mirror can be made in the UHV by the pulse motor. The LIGA process needs the photon energies of 3 kev to 6 kev, the optics of a LIGA beam line generally employ a Pt monolayered-mirror and a Be window, which cuts off low-energy photons. The reflectivity of a Pt-coated mirror is about 55 % in the range of photon energy from 2 kev to 4 kev, however, it drops to 30 % at the photon energy of 6 kev. Therefore, new materials with a high reflectivity must to be found for Deep X-ray lithography (DXL) in this energy range. We propose the use of a Ni/W/C multilayered-mirror with a graded d-spacing in the range of photon energy from 3 ev to 6 kev. The calculated reflectivity of the Ni/W/C multilayered-mirror is higher than 56 % at the photon energy of 6 kev with a glazing incident angle of 0.8 degrees, and photons that have higher photon energy than 6 kev can be removed A 200 µm-thick beryllium (Be) window in a Be window chamber is used to separate the ultra-high vacuum part from the low vacuum part and to cut off low-energy photons. Table 10. Specification of the LIGA exposure system Exposure method Proximity exposure Wafer size 4 inch Exposure area 50 mm(h) 80 mm(v) Exposure environment < 1atm (He-gas)